Clinically, non-melanoma skin cancer (NMSC) is one of the most common malignancies, with more than 900,000 new cases per year in the United States. The Head/neck skin seems only to account for less than 10% of the body's surface area. However, 70 to 80% of NMSCs occur in this region, due to greater sun exposure. Currently, surgical excision is recommended for NMSC treatment, but with significant trauma, postoperative recurrence and complications, and cost. NMSC development is a slow process so that chemoprevention would be a promising strategy. Topical application of chemopreventives is expected to preserve treatment effect and have fewer side effects than a systemic regime. Unfortunately, current strategies, with short-term topical painting, provide very limited benefit. Polymer-made adhesive film (PAF) has been successful for many years in the topical application of analgesics, antibiotics or other medications to tissues, due to its clinical safety, controllable drug release and excellent adherence. Our recent animal studies show that topical PAF application for cancer chemoprevention is safe and effective. Our studies also indicate effectiveness of Celecoxib for such treatment. In this proposed study, we will (1) test local tissue response to topical treatment of PAF-delivered Celecoxib, and optimize Celecoxib dose in normal skin of a mouse model; and (2) determine whether the PAF-Celecoxib patch is effective and safe for topical prevention of UV-induced NMSCs in the same mouse model. This topical PAF-Celecoxib chemoprevention of NMSCs, if successful in this proposed study, will offer a new preventive strategy for skin cancers. It would be an ideal alternative to current surgical excision or other localized treatments. We believe that it will be more effective and produce fewer side effects than current approaches. Furthermore, this therapy will be safe and convenient enough for patients to self-administer at home in the same way as they usually apply a piece of commercial "band-aid" sheet. The same concept will also be applicable to premalignant lesions located on oral, cervical or other tissue surfaces. This is the first study to use polymer biofilm technique for NMSC chemoprevention on head/neck region. We believe that a successful study will greatly benefit patients.